Electricity meters are devices that enable the instantaneous consumption of current and the voltage on an electricity line to be measured with metrological precision, so as to enable the exact electricity consumption of electrical equipment to be billed, e.g. in a house. In known manner, such meters include one or more electromechanical type relays that make it possible to open or close the electric circuit passing through the meter, so as to establish or disconnect the supply of electricity to the house in question. It may be necessary to open the circuit as a result of detecting a voltage surge upstream from the meter. It may also be necessary to do so in the event of the user not paying for electricity consumption, with the instruction to activate the relay then coming from outside the meter. The relay is generally controlled by electronic means of the microprocessor type housed in the meter itself. In the same manner, closure of the circuit may be controlled from the outside or by components within the meter itself.
Electromechanical relays are components that are subject to wear, and they present a lifetime that depends on the electrical conditions in which they are activated, while the relay is being opened or closed. It can happen that they are severely stressed in the event of electric arcs being struck in uncontrolled manner while opening or closing a circuit.
Document EP 0 108 538 describes an alternating current (AC) electric circuit that may be closed or opened by means of a relay, said relay being connected to an electronic control unit in order to activate opening or closing of the electric circuit when an electrical parameter of the circuit reaches a zero value. The timing of the closing or opening of the electric circuit takes the inertial delay of the relay into account. Nevertheless, the inertial delay is merely predetermined.